This invention relates to a feeding mechanism for fastener driving devices and more particularly to fastening devices used in continuous production lines having a feeding mechanism for feeding successive fasteners into the drive track of the device.
Conventional staple feeding mechanisms must perform the task of feeding and holding the staples in the drive track. In certain devices, sticks of staples are loaded onto a magazine that is angled downward so that the force of gravity aids in pulling the staples down to the nose of the device and into the drive track to be driven therefrom. However, in certain applications, the fastening device may need to be horizontally disposed or disposed at an upward inclination, thus, the force of gravity alone is insufficient to feed and hold the staples in the drive track.
To increase the force on the staples at the nose of the device, a mechanism having a friction clutch and a wheel connected to an electric motor has been used. Thus, as the motor turns, the clutch maintains a certain torque on the wheel which in turn keeps a constant forward force on the staples. When a staple is driven, the remaining staples are fed and held forward toward the drive track. Although this type of feed mechanism works well for its intended purpose, it requires an extra power source to be connected to the device, and is inefficient and expensive.
Other conventional feed mechanisms employ a spring biased pusher which contacts the rearmost staple of the staple stick urging the staples forward along a guide to the drive track. The device is effective in feeding and holding the staples in the drive track, however, when a staple stick has been exhausted, the pusher must be retracted to allow another staple stick to be placed on the guide. In a continuous production line, such interruptions can be disruptive and costly due to lost productivity.